JPH05177486A - Spindle unit - Google Patents

Abstract

PURPOSE:To control an oscillation stroke so easily as well as to prevent any possibility of oil penetration into a bearing surface from occurring. CONSTITUTION:This spindle unit is provided with a thrust guide 24 being slidably set up in a housing 10 and supporting a flange part 11a formed in a spindle 11 in the thrust direction, and a piezoelectric actuator for reciprocating this thrust guide 24 in the axial direction together with the spindle 11 as an oscillation operating unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device for machine tools having an oscillation actuator for reciprocating only a rotating spindle in the axial direction at high frequency.

[0002]

2. Description of the Related Art Conventionally, in this type of spindle device, a journal gas bearing rotatably and axially reciprocally supports a spindle in a housing, and the housing is opposed to one side surface of a flange portion of the spindle. By providing a thrust bearing part in the housing, and providing a cylinder in the housing so as to face the other side surface of the flange part, pressure oil is made to flow into the thrust bearing part and the cylinder, and the pressure of the pressure oil in the cylinder is changed.
The spindle was oscillated in the axial direction.

[0003]

In such a conventional technique, when the main shaft is oscillated, the journal gas rotatably supports the main shaft when oil leaks from the seal portion due to the use of oil. Oil may enter the bearing and cause abnormal heat generation or seizure, high pressure is required to move the main shaft at high speed, and the pump may become large. There were problems such as not being able to perform so fast and being difficult to control the stroke of oscillation.

[0004]

SUMMARY OF THE INVENTION The main spindle device of the present invention has been made to solve the above-mentioned problems, and supports a flange portion formed on a main spindle slidably mounted in a housing in a thrust direction. And a piezo actuator that reciprocates the thrust guide together with the main shaft in the axial direction as an oscillation actuating device.

[0005]

With the above structure, the oscillation frequency can be increased by using the piezo actuator, and the stroke of oscillation can be easily controlled by controlling the voltage applied to the piezo actuator.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a machine tool housing, and 1
Reference numeral 1 denotes a main shaft that is rotatably supported within the housing 10 about a vertical axis. A cover 12 is attached to the outer periphery of the housing 10.

In the housing 10, journal bearing members 20 and 21 are mounted at intervals in the axial direction of the main shaft 11, and journal bearings 22 and 23 are formed on the inner periphery of the journal bearing members 20 and 21. Has been done. Pressurized gas is supplied to these journal bearings 22 and 23 to support the main shaft 11 under static pressure. A thrust guide 24 is slidably inserted between the journal bearing members 20 and 21 in the housing 10 in the axial direction of the main shaft 11. Thrust bearings 25 and 26 are formed on the thrust guide 24 so as to sandwich the flange portion 11a formed on the main shaft 11, and pressurized gas is supplied to the thrust bearings 25 and 26 to move the flange portion 11a in the thrust direction. Supports static pressure.

Between the thrust guide 24 and the journal bearing member 21, a plurality of springs 27 for pressing the thrust guide 24 downward are provided on the circumference. A hollow cylindrical member 30 is fitted around the outer periphery of the journal bearing member 20, and a plurality of cylindrical holes 31 are formed in the hollow cylindrical member 30 in the axial direction on the circumference. A stroke bearing 32 is fitted in these cylindrical holes 31, and a pin 33 is fitted in the stroke bearing 32 so as to be slidable in the axial direction. One end of the pin 33 contacts the thrust guide 24,
The other end is in contact with the lever 34.

The lever 34 has a pin 35 inside the housing 10.
A plurality of levers 34 are rotatably inserted around the fulcrum, one end of the lever 34 farther from the fulcrum contacts the pin 33, and the other end closer to the fulcrum has a pin 35 on the housing 10.
It is in contact with a piston 36 slidably inserted in a direction parallel to. In the housing 10, an oil passage 40 communicating with a piezo section described later and an oil passage (not shown) shorter than the oil passage are bored in parallel with each other on the circumference, and a radius from the oil passage 40 and the short oil passage not shown is formed. An oil passage 41 is bored in the direction, and the oil passage 41 communicates with an annular groove 42 formed in the inner circumference of the cover 12. As a result, a plurality of short oil passages (not shown) formed on the circumference communicate with the oil passage 40 through the annular groove 42.

On the inner circumference of the cover 12 and the outer circumference of the piston 36, annular concave grooves 43, 44, 45, 46 are formed, respectively.
The O-rings 47, 4 are provided in the annular grooves 43, 44, 45, 46.
8, 49 and 50 are fitted and sealed at that part. The oil passage 40 communicates with the oil passage 51 of the piezo portion fixed to the housing 10.

In the piezo part, as shown in FIG.
2 is an actuator housing and 53 is a cylinder housing. The cylinder housing 53 is bonded to one end of the actuator housing 52, and the other end of the actuator housing 52 is closed by a cap 54. A piston rod 55 is slidably inserted in the actuator housing 52, and a spring 5 for pressing the piston rod 55 backward is provided between the actuator housing 52 and the piston rod 55.
6 has been intervened. Also, the piston rod 55 has
A piezo actuator 57 whose volume expands according to the current value is inserted from one end thereof. A piston 58 is fitted on the other end, and the piston 58 is slidably guided by the cylinder housing 53. An annular groove 60 is engraved on the outer periphery of the piston 58, and an O-ring 61 is fitted in the annular groove 60 to seal that portion.

Oil is filled in the short oil passages (not shown), the oil passages 40, 41, 51 and the annular groove 42. Next, the operation of oscillating the spindle device of this embodiment will be described based on the above-described configuration. Due to the volume expansion of the piezo actuator 57 in the piezo portion, the piston 58 is slightly displaced via the piston rod 55, and the micro displacement causes the piston 36 to be displaced through the oil enclosed in the oil passages 40, 41, 51 and the annular groove 42. Is displaced and lever 3 closer to the fulcrum
When the piston 36 pushes one end of 4, the displacement of the other end farther from the fulcrum is enlarged, and the main shaft 11 is pushed up together with the thrust guide 24 via the pin 33.

With the above structure and operation, there is no risk of oil intruding into the bearing surface, and the piezo actuator 5
By using 7, the oscillation frequency can be increased, and by controlling the voltage applied to the piezo actuator 57, the stroke of oscillation can be easily controlled. In the above embodiment, the piezo actuator 57 is used as a means for moving the main shaft 11 up and down, and a minute displacement of the piezo actuator 57 is amplified by the piston 36 and the lever 34 to move the main shaft 11 together with the thrust guide 24. Figure 3
As shown in FIG. 7, a structure in which the thrust guide is directly oscillated by using the large displacement piezoelectric actuator 100 may be used.

[0014]

As described above, in the spindle device of the present invention, by using the piezo actuator for oscillation, the oscillation frequency can be increased and the voltage applied to the piezo actuator can be controlled. This makes it possible to easily control the stroke of oscillation.

Further, there is no possibility that oil will enter the bearing surface, and there will be no risk of abnormal heat generation or seizure due to oil leakage.

[Brief description of drawings]

FIG. 1 shows a spindle device according to an embodiment of the present invention.

FIG. 2 shows a piezo section communicating with an arrow (A) in FIG.

FIG. 3 shows a spindle device according to a second embodiment of the present invention.

[Explanation of symbols]

 11 Spindle 24 Thrust Guide 33 Pin 34 Lever 36 Piston 57 Piezo Actuator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriyasu Hayashi 1-1, Asahi-cho, Kariya city, Aichi Toyota Koki Co., Ltd.

Claims (1)

[Claims] 1. A housing, and a main shaft supported in the housing so as to be rotatable and axially reciprocable.
In a spindle device including an oscillation actuator that reciprocates the spindle in an axial direction, a thrust guide slidably installed in the housing to support a flange portion formed on the spindle in a thrust direction, and the oscillation. A spindle device comprising a piezo actuator that reciprocally moves the thrust guide together with the spindle in an axial direction as an actuating device.